In recent years, use of a transparent plastic film as an electrode substrate instead of a glass sheet has been studied for displays (e.g., liquid crystal display and electroluminescence (EL) display) in order to implement a reduction in thickness, a reduction in weight, an improvement in flexibility, and the like.
A transparent plastic film used for these applications is normally required to have heat resistance and low birefringence.
A melt extrusion method and a solution casting method have been known as a method for producing a heat-resistant optical film. However, a film obtained using a melt extrusion method tends to have large in-plane retardation. A film obtained using a solution casting method has reduced in-plane retardation, but has a problem in that the molecular chain may be oriented in the thickness direction when drying the solvent, and an increase in retardation in the thickness direction may easily occur.
Patent Document 1 discloses a resin composition that includes an amorphous thermoplastic resin and a bis(meth)acrylate that can be cured by applying active energy rays as a resin composition that may be used as an alternative to glass and exhibits good chemical resistance and heat resistance. A member obtained using the resin composition is described in the examples of Patent Document 1. However, Patent Document 1 is silent about the birefringence of the member.